#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <conio.h>

typedef int *LIST_PTR;

void fget_list(LIST_PTR *list, int *count);
int linear_search(LIST_PTR list, int count, int target);
void remove_int(LIST_PTR list, int count, int loc);
int menu(void);
void pause(void);

main()
{  int choice;
   int count,i,pos,target;
   LIST_PTR list;

   do
   {  choice = menu();
      
      switch(choice)
      {
       case 1 : clrscr();   /* add an integer in the file */
		printf("To be implemented by YOU!");
		pause();
		break;

       case 2 : clrscr();   /* deletes an integer from the file */
		free(list);
		fget_list(&list,&count);
		printf("Enter the number you wish to remove: ");
		scanf("%d",&target);
		pos=linear_search(list,count,target);
		if (pos != -1)
		   remove_int(list,count,pos);
                else
		   printf("Sorry, no such number exists!");  

		pause();
		break;
	       
       case 3 : clrscr();   /* display all numbers in the file in step of 15*/
		free(list);
		fget_list(&list,&count);
		for (i=0; i<count; i++)
		{  if ((i+1)%15==0)
		      pause();      
		   printf("%d\n",list[i]);
                }
		pause();
		break;
	       
       case 4 : clrscr();  /* searches for a given mumber in the file */
		free(list);
		fget_list(&list,&count);
		printf("Enter the number you wish to search: ");
		scanf("%d",&target);
		pos=linear_search(list,count,target);
		if (pos != -1)
		   printf("The number %d was found at line %d\n",target,pos+1);
                else
		   printf("Sorry, no such number exists!");  

		pause();
		break;
		
       case 5: free(list);
               return 0;
     }
   } while (choice != 5);
 return 0;
 }


  int menu(void)
  { int choice,stat;
    do
    {
      clrscr();
      printf("1.  Add an Integer\n");
      printf("2.  Remove an Integer\n");
      printf("3.  Display all Integers\n");
      printf("4.  Search for an integer\n");
      printf("5.  Exit\n\n");
      printf("Please, enter your choice: ");
      stat=scanf("%d", &choice);
      fflush(stdin);
     } while(stat==0 || choice < 1 || choice > 5);
    return choice;
  }


 /* reads all the integers in the file integer.dat into a dynamic array */
void fget_list(LIST_PTR *list, int *count)
{  FILE *inp;
   int n;
   LIST_PTR p;
   int cnt=0,i;

   inp=fopen("c:integers.dat","r");
   while (!feof(inp))
   { fscanf(inp,"%d",&n);
     cnt++;
   }
   rewind(inp);
   p=(LIST_PTR)malloc(cnt*sizeof(int));
   for (i=0; i<cnt; i++)
      fscanf(inp,"%d",&p[i]); 
   *list=p;
   *count=cnt;       
   fclose(inp);      
}

// searches and returns the location on an integer n if found, -1 otherwise
int linear_search(LIST_PTR list, int count, int target)
{  int loc=0;
   while (loc < count && list[loc] != target)
        loc++;
   if (list[loc] == target)
      return loc;
    else
       return -1;
 }


// removes an from from a given location from the integer.dat file
void remove_int(LIST_PTR list, int count, int loc)
{ int i;
  FILE *outp;
  outp=fopen("c:integers.dat","w");
  for (i=0; i<count; i++)
    if (i == loc)
       printf("The integer %d has been removed\n\n",list[i]);
    else
       fprintf(outp,"%d\n", list[i]);
  fclose(outp);
}


  void pause(void)
  {
    printf("\n\nPress any key to continue...");
    getch() ;
  }